Control device for the stopper-rod of a foundry pouring vessel

ABSTRACT

A control device for controlling the position of a foundry pouring vessel stopper-rod with respect to a pouring orifice. Long-travel raising means raise the stopper-rod off the pouring orifice when opening the orifice after which short-travel means lower the stopper-rod toward the orifice whereby the flow rate through the orifice is initially higher than the normal flow rate so as to initially heat the region around the orifice and melt any solidified metal adjacent the orifice.

United States Patent [19] Pflaum 111 3,733,014 May 15, 1973 CONTROL DEVICE FOR THE STOPPER-ROD OF A FOUNDRY POURING VESSEL [75] inventor: Kndre jdsbh Piiah'mfflaidires,

France [73] Assignee: Societe Des Fonderies De Pont-A- Mousson, Nancy, France [22] Filed: Mar. 30, 1971 [211 App]. No.: 129,459

[30] Foreign Application Priority Data 4/1958 Carllton....ll.. ;:i..I.:....222]04 Po IiEIoN PATENTS'OR APPLICATIONS 576,246 3/1946 Great Britain .Q ..222/DIG.5

Primary Examiner-Robert B. Reeves 4ssistant Examiner --Frederick R. Handren Attorney-J. oeiam'S 1 571 ABSTRACT orifice after which short-travel means lower the stopper-rod toward the orifice whereby the flow rate through the orifice is initially higher than the normal flow rate so as to initially heat the region around the orifice and melt any solidified metal adjacent the orifice. I A

4 Claims, 4 Drawing Figures CONTROL DEVICE FOR THE STOPPER-ROD OF A FOUNDRY POURING VESSEL The present invention relates to the control of stop per-rods of vessels for pouring liquid iron or other metal.

Pneumatic or hydraulic control devices employing fluid motors or cylinder devices are known for raising the stopper-rod for pouring the metal out of the vessel. These controls are so arranged as to raise the stopperrod the required distance to afford a given annular section of passage for the liquid metal between the pouring orifice and the stopper-rod whereby a given pouring rate is achieved. The controlling fluid motor therefore has a given travel. 1

Now, the applicant has discovered that the pouring orifice tends to become clogged by the deposit of solidified metal. This is due to the fact that the temperature of the refractory lining of the pouring orifice and of the liquid metal in the vicinity of the pouring orifice is relatively low, above all when the vessel contains over a rather long period of time an amount of liquid metal which is small relative to its capacity so that the metal cools down. There results an indeterminate modification in the pouring rate and even a sticking of the stopper-rod on its seat.

An object of the invention is to provide a control device for a stopper-rod of a pouring vessel which is so improved as to remedy this drawback and ensure a constant pouring rate.

The invention provides a control device comprising long-travel means for raising the stopper rod and means for lowering the stopper-rod and having a shorter travel.

In one embodiment of the invention, the device comprises in combination, a reciprocable raising element for raising the stopper-rod, a withdrawable abutment engageable in an operative position in the return path of said raising element, and actuating means for first shifting said raising element in such manner that the stopper-rod fully opens said pouring orifice in the course of its opening, then shifting said withdrawable abutment so as to place it in its operative position in the return path of said raising element and finally causing said raising element to effect a return travel limited by said abutment in its operative position so as to reduce the passage section of the pouring orifice but not close said passage.

The element for raising the stopper-rod and the abutment can in particular comprise two pistons mounted inside a fixed cylinder of a linear fluid motor.

Owing to the invention, with the stopper-rod first raised to provide a large opening (maximum travel of the raising element) a large flow of liquid metal occurs through the pouring orifice and heats the relatively cool refractory walls after having re-melted and discharged the metal which had solidified in the region around the pouring orifice. Then the stopper-rod is' partly lowered by the return of the raising element down into abutment with the abutment, brought to its operative position, so as to maintain only a reduced opening and thus regulate and limit the flow of metal. At this moment, notwithstanding the fact that the passage section is smaller, the liquid metal does not cool in contact with the previously heated walls. Thus, there is no obstruction to the flow.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawing.

In the drawing:

FIG. 1 is a diagrammatic sectional view of a device according to the invention for controlling the stopperrod of a pouring vessel, the rod being in its orificeclosing position;

FIG. 2 is a view similar to FIG. 1 of the device, the stopper-rod being in its position for fully opening the orifice;

FIG. 3 is a similar view of the device, the stopper-rod being in a position affording a reduced opening of the orifice, and

FIG. 4 is a partial sectional view of a modification of the control device in the orifice-closing position.

In the illustrated embodiment, the invention is applied to a pouring vessel 1 which has a refractory lining and contains molten or liquid metal A, for example iron. The vessel 1 comprises a pouring orifice 2 and a stopper-rod 3 for closing the latter. The stopper-rod 3 is shifted by a linear fluid motor V having a cylinder 4 fixed to the vessel 1.

The fluid motor contains two pistons arranged inseries, namely a lower piston 5 constituting a withdrawable abutment movable between a withdrawn lower po' sition (see FIGS. 1 and 2) and an upper operative position (see FIG. 3), and an upper piston 6 constituting an element for raising the stopper-rod 3.

The abutment piston 5 is downwardly extended by a rod 7 which extends through the bottom wall of the cylinder 4 and is screwthreaded at 8. Screwed on the screwthreaded end 8 is a nut 9 which adjusts, by abutting against the bottom wall of the cylinder 4, the travel of the rod 7, that is, theupper operative abutment position of the piston.

The piston 6 is upwardly extended by a rod 10 integral with a cross member 1 1 for shifting the stopper-rod 3. The rod 10 has a diameter exceeding that of the rod 7 so that the effective section of the lower face of the abutment piston 5 exceeds that of the upper face of the piston 6. Three fluid conduits 12, 13, 14 communicate with the inside of the cylinder 4. The conduits 12 and 14 are connected to the ends of the cylinder respectively below the lower face of the piston 5 and above the upper face of the piston 6, and the conduit 13 communicates with the inside of the cylinder between the confronting faces of the pistons 5 and 6.

Each conduit l2, l3, 14 is connected to a supply conduit supplying fluid under pressure or to a discharge conduit 16 by three-way electrovaives l7, 18, 19 symbolically represented in the form of slide valves having two positions. The slide of each valve is subjected to the opposing actions, of an electromagnet 20 and areturn spring 21. For the position a of the slide of each valve, the conduit 12, 13 or 14 is connectedto the supply conduit 15. In the other position b, the conduit 12, 13 or 14 is connected to the discharge conduit 16.

The control device operates in thefollowing manner:

Before pouring, the stopper-rod 3 is in the position for completely closing the pouring orifice 2 (FIG. 1). This position has been reached by supplying fluid under pressure to the conduit 14 and by connecting the conduits l3 and 12 to discharge, the eleetrovalves being in the positions shownjn FIG. 1. In this position, the abutment piston 5 is withdrawn and bears against the lower end wall of the cylinder 4 and the piston 6 bears against the piston and is located at the maximum distance x from the upper end wall of the cylinder 4.

To pour metal, the pouring orifice 2 is first opened widely by raising the stopper-rod 3 to the upper position shown in FIG. 2, this being achieved by connecting the conduit 14 to discharge and supplying fluid under pressure to the conduits 12 and 13. The lower abutment piston 5 remains stationary since the same pressure is exerted on its upper large face and on its lower annular face. On the other hand, the upper piston 6 rises a distance x until it abuts the upper end wall of the cylinder 4. The stopper-rod 3 is raised the distance x (FIG. 2) and completely opens the orifice 2 and allows the iron to flow at a high flow rate. This iron heats the refractory walls of the pouring orifice 2. This high rise x of the stopper-rod 3 is only temporary and lasts a short period (of the order of 1 second for a stopper-rod of normal dimensions and longer in the case of large stopper-rods).

Indeed, immediately after, the conduit 13 is connected to discharge and the conduit 14 is again supplied with fluid under pressure (FIG. 3). The abutment piston 5 rises a distance y until the nut 9 abuts the bottom wall of the cylinder 4 and the piston 6 descends but, owing to the fact that the rod 7 has a smaller diameter than the rod 10, the section of the piston 5 on which is upwardly exerted the pressure of the fluid from the conduit 12 exceeds that of the piston 6 on which the pressure is exerted downwardly, so that the force raising the piston 5 is greater than the force lowering the piston 6. The piston 5 therefore remains in its upper operative position at a distance y above the bottom wall of the cylinder 4 and is not shifted by the piston 6. The latter can thus only descend from the upper position shown in FIG. 2 a distance (x-y).

The stopper-rod 3 is therefore brought nearer to the pouring orifice 2 at a distance y from the seat so as to throttle or reduce the passage section and limit the flow of iron.

To stop the flow or iron, the valves l7, l8, 19 are brought to the positions shown in FIG. 1.

Thus it can be seen that the procedure is in two stages for opening the orifice 2, namely a short first stage for widely opening the orifice by a great rise x of the stopper-rod 3 and a second longer stage for a limited opening of the orifice by a lowering of the stopper-rod 3 without, however, closing the orifice (travel x-y) so as to limit and regulate the flow of metal through the pouring orifice.

The high rate of heating the refractory wall of the orifice 2, due to the initially high rate of flow of the iron, precludes solidification of the iron in the vicinity of the orifice 2 and an obstruction of the latter, even when the stopper-rod 3 is in a position for reducing the passage section of the orifice 2 (FIG. 3).

The rate of flow ofthe iron can be regulated by modifying the travel y of the abutment piston 5 by means of the nut 9 screwed on the screwthreaded end 8.

FIG. 4 shows a modification in which the top of the piston 6 is permanently subjected to a pressure lower than the supply pressure in the conduit 15, through the conduit 14a and a pressure reducing valve D. An electrically operated distributor valve 22 having 4 ways connected to conduits l5, 16, 12a, 13a and three positions, replaces the three electrovalves of the first embodiment.

Other modifications are possible. Thus, the control device having a fluid motor comprising a cylinder 4 and two pistons 5 and 6 can be replaced by any other double-acting control device having a long travel for the high raising of the stopper-rod 3 and a full opening of the orifice 2 and a short travel for lowering the stopperrod 3 without however closing the orifice 2.

There may be arranged, for example, two fluid motors connected in series or a fluid motor and a mechanical device arranged in series or two mechanical devices, for example of the rack and pinion type, connected in series.

Having now described my invention what I claim and desire to secure by Letters Patent is:

l. A control device comprising a foundry pouring vessel stopper-rod and pouring orifice, a reciprocable raising element having a forward travel and return travel and associated with said stopper-rod for raising the stopper-rod off said pouring orifice, a withdrawable abutment engageable in an operative position thereof in the path of the return travel of said raising element, and actuating means adapted and arranged to first shift said raising element in such manner that the stopperrod fully opens said pouring orifice in the course of its opening, then shift said withdrawable abutment so as to place it in said operative position and finally causes said raising element to effect a return travel limited by engagement with said abutment in said operative position so as to reduce the section of a passage between said stopper-rod and pouring orifice but not close said passage, wherein said raising element comprises a piston and said withdrawable abutment comprises a piston, said two pistons being mounted inside a cylinder of a linear fluid motor which is fixed with respect to said pouring orifice.

2. A control device as claimed in claim 1, wherein the fluid motor comprises a cylinder and two double-face pistons and two rods, a first of said pistons having a rod of smaller diameter than the rod of a second of said pistons, a first fluid conduit and a second fluid conduit communicating respectively with the interior of the cylinder adjacent end faces of the first and second pistons, and a third fluid conduit communicating with the interior of the cylinder between the two pistons, 3-way valves associated with said conduits for selectively connecting said conduits to a supply conduit supplying fluid under pressure and to a discharge conduit, the arrangement being such that first said second piston is shifted when moving said stopper-rod away from said pouring orifice and then said first piston constituting the withdrawable abutment is shifted to said operative position and thereafter said second piston is shifted in a direction for returning said second piston and moving said stopper-rod toward said pouring orifice into abutting relation to said first piston whereby the section of the passage between said stopper-rod and said pouring orifice is reduced but not closed.

3. A control device as claimed in claim 1, wherein one of said pistons is a first double-face piston corresponding to said abutment and the other of said pistons is a second double-face piston corresponding to said raising element, a first conduit and a second conduit respectively communicating with the interior of the cylinder adjacent remote end faces of said pistons, a third conduit communicating with the interior of the cylinder between said pistons, a four-way distributor valve having three positions associated with said first conduit and third conduit for selectively connecting said first conduit and said third conduit to a supply conduit supplying fluid under pressure and to a discharge conduit, said second conduit being connected through a pressure-reducing valve to said supply conduit so that the fluid supplied to said cylinder above said second piston is at a pressure lower than that of the fluid which arrives by way of said first and third conduits whereby said raising element is first shifted when moving said stopper-rod away from said pouring orifice then said withdrawable abutment is put in said operative position inder. 

1. A control device comprising a foundry pouring vessel stopperrod and pouring orifice, a reciprocable raising element having a forward travel and return travEl and associated with said stopper-rod for raising the stopper-rod off said pouring orifice, a withdrawable abutment engageable in an operative position thereof in the path of the return travel of said raising element, and actuating means adapted and arranged to first shift said raising element in such manner that the stopper-rod fully opens said pouring orifice in the course of its opening, then shift said withdrawable abutment so as to place it in said operative position and finally causes said raising element to effect a return travel limited by engagement with said abutment in said operative position so as to reduce the section of a passage between said stopper-rod and pouring orifice but not close said passage, wherein said raising element comprises a piston and said withdrawable abutment comprises a piston, said two pistons being mounted inside a cylinder of a linear fluid motor which is fixed with respect to said pouring orifice.
 2. A control device as claimed in claim 1, wherein the fluid motor comprises a cylinder and two double-face pistons and two rods, a first of said pistons having a rod of smaller diameter than the rod of a second of said pistons, a first fluid conduit and a second fluid conduit communicating respectively with the interior of the cylinder adjacent end faces of the first and second pistons, and a third fluid conduit communicating with the interior of the cylinder between the two pistons, 3-way valves associated with said conduits for selectively connecting said conduits to a supply conduit supplying fluid under pressure and to a discharge conduit, the arrangement being such that first said second piston is shifted when moving said stopper-rod away from said pouring orifice and then said first piston constituting the withdrawable abutment is shifted to said operative position and thereafter said second piston is shifted in a direction for returning said second piston and moving said stopper-rod toward said pouring orifice into abutting relation to said first piston whereby the section of the passage between said stopper-rod and said pouring orifice is reduced but not closed.
 3. A control device as claimed in claim 1, wherein one of said pistons is a first double-face piston corresponding to said abutment and the other of said pistons is a second double-face piston corresponding to said raising element, a first conduit and a second conduit respectively communicating with the interior of the cylinder adjacent remote end faces of said pistons, a third conduit communicating with the interior of the cylinder between said pistons, a four-way distributor valve having three positions associated with said first conduit and third conduit for selectively connecting said first conduit and said third conduit to a supply conduit supplying fluid under pressure and to a discharge conduit, said second conduit being connected through a pressure-reducing valve to said supply conduit so that the fluid supplied to said cylinder above said second piston is at a pressure lower than that of the fluid which arrives by way of said first and third conduits whereby said raising element is first shifted when moving said stopper-rod away from said pouring orifice then said withdrawable abutment is put in said operative position before the return of the second piston when lowering the stopper-rod so as to reduce the section of a passage between said stopper-rod and pouring orifice but not close said passage.
 4. A control device as claimed in claim 2, wherein the rod of said first piston has a screwthreaded end portion and carries a nut engaged on said portion and acting as an abutment engageable against an end wall of said cylinder. 